Prytanis

Prytanis is the Preceptor of the Order of the Seekers After the First Truth, a Latarran delegation member at the Emperor's Council whose body has been entirely dissolved away, leaving only a brain suspended in a tank of greenish liquid and carried on a palanquin by robed attendants. The Seekers seek adorator status within the Imperium and devote themselves to contemplating what they call the Message and the Meaning -- monitoring the background radiation of creation for what they interpret as the syllables of God's words.

Three days before the Council's end, the Seekers detect two anomalous spikes in background radiation. Prytanis presents Hadrian with a paper showing the pattern and asks three times what the signal means, receiving no clear answer. In Hadrian's final moments on the scaffold, Prytanis is one of two individuals who manage to pass him a message -- a small roll of paper beginning with the words "Marlowe! Marlowe!"